How to Convert PNG to JPG on a Mac
A Mac screenshot taken in the most compatible format is a PNG, and plenty of upload forms want a JPG. Preview and Finder both convert one with nothing installed. Apple's steps for each, and what happens to transparency.
To convert PNG to JPG on a Mac, such as a screenshot sitting on your desktop, open it in Preview, choose File > Export, pick JPEG from the Format pop-up menu, and click Save. Preview comes with macOS, so nothing needs installing. Finder can also convert the file where it sits, without opening it.
A common source of PNG files on a Mac is the Mac itself, because PNG is the Screenshot app's most compatible capture format. If you would sooner convert an image in your browser, PNG to JPG does it without uploading the file. The menu steps below follow Apple's user guides, which showed macOS 27 Golden Gate as the current version when we read them on 13 October 2026.
Why are Mac screenshots PNG files?
A Mac screenshot is a PNG file whenever the Screenshot app captures in its most compatible format. Apple's support article Take a screenshot on Mac lists two capture formats in the app's Options menu, on supported Mac models using macOS Tahoe 26 or later: "SDR (Most Compatible)", which uses the PNG image format, and HDR, which uses HEIF. JPEG is not on that list, so the Options menu has no JPG choice.
The same article says screenshots save to your desktop by default, which is where to look for the file. A screenshot captured in HDR is a HEIF file and not a PNG, and our guide to converting HEIC to JPG on a Mac covers that format.
How to convert PNG to JPG in Preview
To convert PNG to JPG in Preview, export the file and change its format on the way out. These steps are from Apple's Preview User Guide page Convert image file types using Preview on Mac.
- Open the PNG in Preview.
- Choose File > Export.
- Click the Format pop-up menu and choose JPEG.
- Set the quality. Apple notes that if you choose JPEG, "you can adjust the image's quality."
- Type a new name or pick a new location, then click Save.
For a folder of screenshots, Apple's tip on that page is to open the files in one window, select them in the window's sidebar, and follow the same steps.
Apple's page does not say what Preview does with a PNG's transparent areas when the export format is JPEG. JPG cannot store transparency, so if your PNG has a see-through background, open the exported file and check what colour it was given.
How to convert a PNG from Finder without opening it
To convert a PNG from Finder, use the Convert Image quick action. Apple's Mac User Guide page Perform quick actions in the Finder on Mac describes it as a way to convert an image to another format or a smaller size.
- Select the PNG in a Finder window or on your desktop.
- Control-click it and choose Quick Actions.
- Click More, then choose Convert Image.
- Choose JPEG as the format, and choose a size.
The size choice is the reason to pick this route for a large screenshot you plan to email: one action changes the format and can shrink the picture. Apple says the tasks in the Quick Actions menu depend on the file type and on which Finder extensions are enabled. Choosing Customize under More opens the Extensions settings, where Finder extensions are managed.
How to convert PNG to JPG on a Mac in your browser
To convert PNG to JPG in a browser, open PNG to JPG, add your files, and download the JPGs. The image is drawn and re-encoded inside the browser tab and is not uploaded. A Mac doesn't need this route, since Preview and Finder do the job. It is useful when the PNG has a transparent background and you want to know what fills it, or when you want a whole batch back as one zip.
- Open PNG to JPG in your browser.
- Add your PNG files. The tool accepts PNG only, up to 50 files at a time and up to 50MB per file.
- Set the JPG quality slider. It starts at 0.92 and runs from 0.4 to 1, and a lower number gives a smaller file.
- Convert, then download. A single PNG comes back as a JPG file, and a batch comes back as one zip.
The JPG keeps the PNG's pixel dimensions and its file name with a new ending, so diagram.png becomes diagram.jpg. Transparent areas are filled with white. In our test, a 1600 x 1000 PNG with a transparent corner came back as a 1600 x 1000 JPG with that corner solid white.
Should a screenshot be a JPG at all?
It depends on what the screenshot shows. JPG is built for photographs, and its compression blurs the hard edges of small text and interface lines. A screenshot of a photo or a video frame converts well. A screenshot of a document or a settings window is better left as a PNG unless the form you are filling in refuses PNG.
Our guide on when to convert PNG to JPG and when not to goes through that choice in full. If the file has to stay a PNG, Compress PNG returns a PNG and keeps its transparency. If you need transparency in a format other than PNG, PNG to WebP keeps it, which JPG can't.
FAQ
Can a Mac save screenshots as JPG directly?
Not from the Screenshot app's Options menu. Apple's screenshot article lists PNG and HEIF as the capture formats and does not list JPEG. This guide covers converting after the capture, with Preview, the Convert Image quick action, or PNG to JPG.
What happens to a transparent PNG when it becomes a JPG?
The transparency is replaced by a solid colour, because JPG cannot store it. PNG to JPG fills it with white. Apple's Preview page does not name a fill colour, so check a Preview export by eye.
Does converting change the image's dimensions?
PNG to JPG keeps the PNG's width and height, and Apple's Preview export steps include no size setting. The Convert Image quick action asks you to choose a size as well as a format, so check which size you pick. To change dimensions on purpose, see how to resize an image on a Mac.
Will the JPG look worse than the PNG?
JPG is lossy and PNG is lossless, so the JPG is not an exact copy. On photographic content at a high quality setting the difference is hard to see. On text it shows sooner. JPG vs PNG explains the trade, and what a PNG file is covers the format.